Which statement is true?

Which statement is true?
A . An IPv6 address is 64 b long and is represented as hexadecimal characters.
B . An IPv6 address is 32 b long and is represented as decimal digits.
C . An IPv6 address is 128 b long and is represented as decimal digits.
D . An IPv6 address is 128 b long and is represented as hexadecimal characters.

Answer: D